This invention relates to the field of transportation, and particularly to trailers to be towed behind draft vehicles to transport bulky loads such as commercial farm machinery. While such machinery is of course wheeled, for movement over the ground in performing its normal function, the construction is such that no reasonable highway speed can be obtained from the vehicle on its own wheels, and when such a machine is initially delivered, transferred to a different owner, or even moved from place to place in a single large farm complex, it is customary as well as necessary for efficiency to load the machine in a vehicle designed for highway use.
Trailers of many kinds are known, and have in common a load carrying bed or body, running gear in the form of single or multiple wheels, and rigging such as a tow bar for coupling the trailer to a draft vehicle. There are of course size limitations, particularly as to the width of such a trailer, when it is used on the public highways, and much large scale farm equipment, such as grain drills for example, is too wide to be moved down the highway in its normal direction, but must be moved sideways. This in turn has presented difficulties in loading a trailer from the rear end as is traditional.
It is also true that a vehicle useful for highway transport may not be satisfactory in the first and last few thousand yards of the journey, which are typically over farmland rather than highway. On such land, the line through the trailer, trailer hitch, and the draft vehicle does not remain straight, but angulates more or less sharply at the hitch as the assembly moves over the crests and dips of rolling country. A unitary trailer bed long enough to transport larger commercial machinery experiences considerable rocking motion under these conditions, and may even drag at the front or rear if conditions are severe.